In recent years, communication networks utilizing multi protocol label switching (mpls) have been rapidly spreading is use. This MPLS first requests a label for each path until the destination communication apparatus to which a packet is to be transmitted is reached, determines an allocated label in response to the request, and realizes the communication with the above described destination communication apparatus according to routing based on the label.
Further, recent there has been a tendency to extend the MPLS to not only the packet layer, but also layers other than the packet layer to realize the above described communication. For this purpose, a communication network enabling application of the signaling techniques in the already existing MPLS to not only the original packet layer, but also layers other than the packet layer, for example, the wavelength layer (or time slot layer etc.) as it is has been proposed. Note that the prior art mentioned here will be explained in detail later by referring to FIG. 25 to FIG. 34.
Note that as known art related to the present invention, there are the following Patent DocuMENT1 to 3.
Patent Document 1: Japanese Unexamined Patent Publication (Kokai) No. 2002-271373
Patent Document 2: Japanese Unexamined Patent Publication (Kokai) No. 2002-84228
Patent Document 3: Japanese Unexamined Patent Publication (Kokai) No. 2001-358771
However, none of these known art suggests the technical idea of the present invention.
When looking at the above Patent Document 1, the plane covered by the Present Document 1 is completely different from the plane covered by the present invention. Namely, a MPLS network can be logically considered divided into a forwarding plane for actually forwarding data packets and a control plane for setting or controlling a label switching path (LSP). Between them, the Present Document 1 relates to the forwarding plane, particularly its input end. Contrary to this, the present invention relates to the control plane, so the two are completely different.
Next, when looking at the above Patent Document 2, the Present Document 2 relates to art utilizing a coding space that combines a wavelength axis and a time axis called an optical code″ in order to provide a larger space as the space of an identifier for a burst in a network performing optical bust switching. Contrary to this, the present invention relates to the setting of a path and the routing of information, therefore, so the two are fundamentally different in this point.
Further, when looking at the above Patent Document 3, the Present Document 3 relates to a method of mapping an input data program to a connection having a variety of qualities of communication. Contrary to this, the present invention relates to a method for setting a connection, that is, signaling, and calculation of a route, that is, routing, therefore the two are completely different.
In the prior art explained in detail later by referring to FIG. 25 to FIG. 34, there are two problems that will be similarly explained in detail later.
The first problem is that information concerning a request from an operator or a user sometimes cannot be utilized when calculating the route of a path.
For this reason, the route of a path of the wavelength layer suitable for accommodating the path of the packet layer, for example, the route of a path of the wavelength layer able to keep the number of wavelengths which newly become necessary to the minimum cannot be selected.
The second problem is that a path setting request message and a path setting acknowledgement message responding to this must be transferred a plurality of times between the communication apparatuses in order to set paths of a plurality of layers, for example, the packet layer and the wavelength layer.
For this reason, the “procedure for path setting” in each communication apparatus becomes complex.